Ernie Bonham and Johnny Beazley during Game 2 of the 1942 World Series, St. Louis, Missouri,October 1, 1942John Andrew Beazley Papers

The 1941 season proved to be a significant year for Beazley. With the help of the Pelicans' manager, Ray Blades, Beazley's pitching was transformed. Blades convinced Johnny that there was more to pitching than just throwing the ball or, as Johnny put it, "fogging the ball past the batters." Blades taught him to change the speed of his pitches and to pitch the ball to different locations. When the St. Louis Cardinals had an opening on their roster that September, the now injury-free and much improved Beazley was called up to the major league team. He was quoted as saying, "I was lucky I had a manager who was so patient. Otherwise I wouldn't be up here winning in the National League."

Scorecard for Game 2 of the 1942 World Series, St. Louis, Missouri, October 1, 1942John Andrew Beazley Papers

Branch Rickey, the Cardinals' general manager and creator of the first baseball farm system, stated,

Beazley is the best young pitcher in our chain. He's better than several we have on the Cardinal staff, and the only reason he is not up there now is that he lacks sufficient poise. The kid has blinding speed, a fine curve, and a good change of pace. And he's smart, too. All Beazley needs to be a winner in the major leagues is to acquire poise. He's got everything else, and I believe he will get the necessary poise this year. We're counting on him strongly for 1942.

Program from Game 2 of the 1942 World Series, St. Louis, Missouri, October 1, 1942John Andrew Beazley Papers

Beazley attended spring training in 1942 along with other young players eager to earn a spot on the big league roster for that year. Remembering his noteworthy performance the previous year, manager Billy Southworth gave him a spot on the roster and, later, in the starting pitching rotation. Only two years after almost calling it quits in the minors, Johnny became the top rookie pitcher and one of the best pitchers in the major leagues during that season. Playing against their rivals, the Brooklyn Dodgers, the Cardinals went on to win the National League pennant and earn a coveted spot in the 1942 World Series. The team faced the defending series champs, the New York Yankees, whose members included baseball greats Joe DiMaggio and Phil Rizzuto. The Yanks won the opening game of the Series but Beazley tied things up by pitching a winning second game. The Cardinals went on to win games three and four, and then Beazley was called upon to pitch game five. Composed and confident, he pitched another winning game, clinching the Series for the Cardinals and earning himself the name "Yankee Killer." While the official Rookie of the Year Award was not given out until 1947, the Chicago Chapter of the Baseball Writers Association of America named Beazley the most valuable rookie of the year for 1942.